This is a micro sized (4,5cm tall) working rocket with launchpad. It flies about 50cm - 5m high, depending on the strength of your spring. To work, at least one ballpoint spring is required.
The total printing time is about 2 hours. You can find a more detailed instruction below or in the pictures.

Instruction:

• Step 1:
  Make sure you have two ballpoint springs. If you have only one, it will work either, but the trigger will not automatically snap in place. The model is designed to fit the most standard sized springs. If you aren't sure, if your spring will fit, you can check it below.
  Maximum dimensions:
  diameter: 5,3mm
  length (normal): 33,5mm
  length (pressed together): 10mm
  If the length is too big, you can simply cut away something.

• Step 2:
  Print the files Launchpad_part1, Launchpad_part2 and trigger. Choose between the normal rocket and the Starship design. No supports needed, except for the Starship file.
  Here are my recommended print settings:
  Rocket: 100% infill, print very slow for a high accuracy
  Starship: 100% infill, print very slow for a high accuracy, supports for the upper wings, make sure not to support the hollow space
  Launchpad_part1: 20% infill and 50mm/s, 100% infill and 10mm/s for the pillar
  Launchpad_part2: 20% infill, 50mm/s
  Trigger: 100% infill, 50mm/s

• Step 3:
  Put one spring in the hollow space of the rocket. (You can optionally glue it in, to make sure it will not fall out. You can also glue it to the Launchpadstump)

• Step 4:
  Put the trigger in the slot of Launchpad_part1. Put the 2nd spring in behind it.

• Step 5:
  Press the spring in and put Launchpad_part2 in the indentation of Launchpad_part1.

• Step 6:
  Put the rocket on the launchpad and make sure it will snap in place. Pull the trigger and have fun.

Tip: You can glue one spring to the rocket and one to the launchpad stump to get even more power.

In future I will try to upgrade this thing depending on your feedback. I will try to release more different rockets and versions for bigger springs.

If you liked this project, I would be happy to see your feedback in the comments.
Thanks for making
Tim